Improvement in grinding-machines



S. TRETHEWEY. 'Gri nding-Maohine.

No. 204,393. Patented May 28,1878.

NJ'HERS, FHOYO-UTROBRAFRER, WASNINGTON. D c.

UNITED STATES PATEN'I'. OFFICE.

SAMUEL TRETHEWEY, OF PITTSBURG, PENNSYLVANIA.

IMPROVEMENT IN GRlNDlNG-MACHINES.

;Specificatlon forming part of Letters Patent No. 204393, dated May 28, 1878; application filed March 7, 1878.

Figure 1 is'a perspective view fron the work- V ing end of the machine, and Fig. 2 is a-vertical central section.

Like letters refer to like parts wherever they occur.

My invention relates to the Construction and operation of machines adapted to grinding metallic and similar rods, especially those where accurate rounds are desirable:

I will now proceed to describe my invention, so that others skilled in the art to which it appertains may apply the same.

In the drawing, A indicates a suitable bed, on which are erected fixed housings B B, and a bracket or rest, G, for a guide. Mounted in the fixed housings B B are rotary housings D D', adapted to journal in each other as well as in the fixed housings.

One of the rotary housings D is much heavier than its follow D', and is bored to form seats for boxes d, controlled by segments d', which can be fixed in any desired position by set-screws d J ournaled eccentrically within the boxes are shafts c, which carry the grinding (preferably emery)ro1ls or wheels 0 said shafts being tapered, as at c so as always to insure a true and even bearing and proper adjust ment of the grinding mechanism.

The shafts c project from the roi ary housing D and enter the rotary housing D where they are provided with two or more friction-wheels c beveled in reverse directiohs, and are held apart by an interposed coiled or other suitable spring, c D' indicates the second rotary (or driving) housing, which'is simply a cylinder having a series of beveled grooves on its interior, the bevel of one half being in reverse direction to the other half, said grooves adapted to receivethe beveled frictionwheels or gear c In lieu of the friction driving-gear, cog-gearing may be employcd; but by the constriction of the gearing and rotary housing, as shown,

it will be found that the spring between the .gearing will keep them in contact with the sides of the grooves in the rotary drivinghousing, so that though the shafts c may be caused to approach in the adjustment of the grinding-wheels, and the periphery of the gears e are lifted away from the bottom of the; grooves, yet the side hearing will insure the proper driving of the work-rolls. cate`s a bracket or standard arranged on the axial line of the rotary housing, said standard forming the support of a tubular or equivalent guide, e, which projects through the machine (or rotary housings) up to within a short distance of the periphery of the grinding rolls or wheels. On the opposite side of the grindingwheels, and close to the peripheries, is a receiving-guide, e', supported in a bracket or rest, G, said guide being also arranged in true aXial line with the rotary housings. These fixed guides, arranged with relation to the grinding mechanism, as specified, give a rigid unchanging hearing or support throughout for the article operated upon, which overcomes the tendency of the rod to spring and insures a true center of rotation for the grindin g mechanism.

A second housing (not shown) may be erected on the bed A, in which may be journaled feed-rolls, the bar being held stationary thereby, or, in other words, prevented from turning, for which purpose feed-rolls are preferred, though the bar may be fed by hand, if desired.

The peripheries of the rotary housings D D' are formed, as shown in the drawings, so that the housings may be driven by belting; but gearing may be substituted therefor, if preferred, and in order to give a reverse motion to one of the housings its driving-belts will usually be crossed.

The operation of my devices is as follows: The bar to be ground, having been inserted in the axial guide e, is fed forward by appropriate mechanism (or by hand) until it is in the bi ght of the grinding rolls or wheels 0 Power having been applied to the rotary housing D, the grinding-wheels are caused to move around the bar to be ground, acting on the surface E indi-,

thereof, and at the same time power by crossbelting or otherwise having been appled to rotary housing D', it moves in reverse direction to D, doubling the speed of wheels 6 through driving-wheels c and shaft c. The bar is thus held upon n fixed axis while the grindng` mechanism revolves around it, and as the bar is fully ground and trued at one point before it is advanced in the guide it will be accurately rounded throughout its entire length.

In my machine, the nxis of the rod being stationary and the grinding mechanisn re- Volving eroud the same, true eirc'les must be described on the periphery of *the bar, and a true round is necessarily obtained. The meth od of gearng and drivng the rolls greatly increases the aceuracy and Capacity of the ma;- chine.

I am aware that a polishing-machine has been heretofore devised wherein flexible revolvng polishingpads, revolving on thei-r own anes and also around the stick being pot ished, were employed, and that in seid conneetion axial guides rot etng with the olish ing mechenism were used, and therefore do not herein claim such subject-matter; but

Having thus described my invention, what I claim, and desire to secure by Letters Pajtent, is

1. In e machine for grindin-g rods, 850., the combinatiou of fixed heusings B B, rotary housings D D' journaled therein, one or more grinding-wheels mounted on shai'ts ad'ustably journaled in the rotary housings, an an axially-arranged fixed guide or guides, substantialiy as specified.

2. The combination of the fixed housings, the two rotary housings journaled on each other, and ada pted to be driven in reverse direetions, the internal driving-gear, and a grinding wheel or wheels adjustably journaled in the rotary housing, substantially as specified.

3. In e machine of the class specified, the eombination of the internafly-grooved rotary housing with the bevel :fiction-gear and the spring for preservng the contact of the gear and housing, to permit the edjustment of the rolls or grinding-wheels, substantially as speci- SAMUEL TRETHEWEY.

witnesses:

R. H. WHITTLESEY, JOHN K. SMITH. 

